Effective monitoring is essential for sample storage and never more so than in the race to halt a pandemic. Gary Bradshaw recalls how improved alarming contributed to the protection of Oxford’s Covid research.
The University of Oxford’s Peter Medawar Building for Pathogen Research is a cross-divisional, multi-disciplinary building focused on research in host-pathogen interactions.
This includes studies of major microbial pathogens, development of models to tackle epidemics and, crucially, a focus on the control of pathogens through vaccine development.
Much of the research has centred around HIV and hepatitis pathogens, and more recently the Covid-19 pandemic, when the university played a key role in understanding the immunopathology of the virus and developing a vaccine.
Samples from hospitalised patients and exposed health care workers were transferred to the lab for storage for research for the development of a vaccine.
The safe and effective storage of pathogens was vital in preserving their phenotype and preventing any damage to the cells.
To ensure this, the samples were kept in two types of freezers in the Medawar Building.
The first resembled a standard freezer, operating at -80oC and was designed primarily for blood plasma storage.
The second consisted of a vessel, cooled using liquid nitrogen and kept topped up using a liquid nitrogen feeder tank. These freezers operated at -180°C and each was capable of storing up to 100,000 individual samples of the pathogen. The facility used around a dozen freezers in total, split across various labs in the building.
Speaking as work progressed on the vaccine, postdoctoral scientist Dr Mathew Jones had emphasised the importance of accurate monitoring: “If the temperature fluctuates outside of safe parameters, we could lose a sample, which would be detrimental to our research, especially as it will become harder to get samples from patients with the disease as it wanes. This is why it’s vital that we’re able to track temperature fluctuations over time.”
To maintain temperature, the facility used an Eltek monitoring system including hardware such as temperature sensors that operated from -200oC to +200°C. The liquid nitrogen maintained a constant temperature of -180oC and a sensor was inserted into the freezer next to the samples. The data from the sensor went to an individual data logger placed on each freezer, and these loggers then transmitted their data to a centralised control system.
Each freezer was also fitted with an alarm that sounded when the sensor detected a temperature that fell outside of safe limits.
The system previously used could send SMS alerts when it detected an alarm condition. However, it would provide SMS alerts to all 10 assigned phone numbers regardless of which freezer had gone down
“One of the biggest issues we had was dealing with an alarm condition, a situation when the temperature would fluctuate outside of the set parameters,” recalled Jones. “In a building like ours, with numerous departments and individual labs, there’s not always someone within earshot of an alarm.
“The nature of the research means that the typical nine-to-five shift is not always feasible. Scientists often have to come into the labs in the early hours to see to an experiment they’re working on. Unless someone is physically present and within earshot of the alarm at all times, the alarm system is not fit for purpose. Even if they are present, not everyone is qualified and permitted to handle liquid nitrogen equipment.”
The system previously used could send SMS alerts when it detected an alarm condition. However, it would provide SMS alerts to all 10 assigned phone numbers regardless of which freezer had gone down, even if it was one degree above the limit. It would continue to send out alerts every half an hour until someone turned it off.
Alerts could result in an hour-long round trip into the lab to reveal that a sensor had dislodged and moved a few inches, so the temperature was being recorded higher than normal. Or a reading might coincide with a door being opened to remove a sample, that would result in the temperature quickly returning to normal.
There was no real-time mechanism for logging in to see the data and assess whether the alarm was a false-positive or a genuine emergency.
Omniflex, which has specialised for 60 years in industrial networking, remote I/O systems, utilities monitoring, process automation systems, signal conditioning and alarm and event management was asked to address the problem.
We supplied the Medawar Building with our Teleterm M3 GSM remote terminal unit (RTU). The device connected using a serial ModBus port to the Eltek Monitoring systems that controlled a number of liquid nitrogen and -80°C freezers.
When the Teleterm M3 detected a temperature fluctuation that exceeded the allowable limits set by the monitoring system, it automatically sent alerts via email or SMS to designated email accounts or mobile phones anywhere in the world.
The user then needed to reply to acknowledge the alarm condition; if the unit failed to receive a response, the system escalated the alert to another set of mobile phones or email accounts.
As well as alerts, a Data2Desktop web portal gave remote access to the system using any web-enabled device. The web-based system also logged all historical events and could automatically generate daily, weekly and monthly reports summarising deviations and alarm events for conformance reporting.
The liquid nitrogen freezers in the lab were connected to an automated system that fed liquid nitrogen into the vats using feeding lines, replenishing them every 24 hours from a feeder tank. If an operator were to leave a valve closed, this could cause a loss of pressure in the freezer and the temperature to rise, leading to an alarm condition.
The user then needed to reply to acknowledge the alarm condition; if the unit failed to receive a response, the system escalated the alert to another set of mobile phones or email accounts
For greater flexibility, Dr Jones had also requested a means of splitting the data into the individual groups that made up the scientific departments in the building, to provide a system where SMS alerts went only to those responsible for that freezer.
Additionally, the installation also provided a means of logging in to observe a real-time feed of the live temperature data, as well as over time [customising] the notifications depending on the time of day, and whether it was in the form of an email or an SMS.
A consequence of being able to track the historical temperature data meant that scientists could also use it in order to conduct a health-check of the freezer.
Because freezers can lose efficiency over time, as the vacuum and internal pressure fell, they may have needed re-priming or replacing, said Jones. By seeing how quickly a given freezer got up to temperature, staff could see how healthy it was and plan in maintenance or upgrades noted.
Pics: Shutterstock, Steve Cornfeld
Gary Bradshaw is director at Omniflex
